Torque measuring apparatus



y 1944- E. E. SIMMONS, JR 2,350,072

TORQUE MEASURING APPARATUS Original Filed Feb. 23, 1940 83a. 65 5/ I6263b 62? I as V 83c INVENTOR IT Hirer/E SIMMON Patented May 30, 1944TORQUE MEASURING APPARATUS Edward E. Simmons, Jr., Pasadena, Calif.

Original application February 23, 1940, Serial No. 320,327. Divided andthis application Jannary 1, 1942, No. 425,359

5Claims.

This invention relates generally to force measuring apparatusparticularly for torque.

It is an object of my invention to provide improved means whereby thetorque of a shaft may be measured with a high degree of sensitivity andaccuracy in a simple and direct manner. A further object is to provideimproved torque measuring apparatus in which the force responsiveelement is subjected directly to a tension load without involvingcomplications incident to diagonal tension stresses in a shaft. Afurther object is to provide an improved torque measuring apparatus thatcan, if desired, be employed in connection with a rotary type impacttesting machine wherein a specimen may be broken without impairing theoperativeness of the torque measuring apparatus.

Other objects and advantages will be more apparent to those skilled inthe art from the following description of the accompanying drawing inwhich:

Fig. 1 is a diagrammatic sectional illustration of a torsionaldynamometer employing my invention; and

Fig. 2 is a plan view of Fig. 1.

Torsional impact machines of a well-known type employ a specimen one end01 which is normally held against rotation and the other end of which isfree to rotate upon application of a sudden torsional impact loadapplied thereto, such a machine being shown for example in Luerssen etal. Patent No. 1,962,604.

To measure the torsional load imposed upon a specimen, I suitably clampor support the same as by a squared end on the specimen shank in anS-shaped. strain responsive member 83a which in turn, is bolted at 85 orotherwise suitably secured to a stationary frame 83b. The free end ofthe specimen 83 is provided with a usual strike bar 830 extendingcrosswise of the specimen axis. This cross bar may be hit in any desiredmanner, for example, as shown in said Patent No. 1,962,604 wherebytorque is imparted to the specimen. Strain sensitive filaments arapplied at N and 84" to the relative thin tangential sides or arms BIand 82 of the s member so as to act in tension for an application oftorque to the square ended specimen. The strain sensitive filamen aremore fully disclosed in' my copending application Serial No. 320,327filedFebruary 23, 1940, now Patent No. 2,292,549, granted Aug. 11, 1942,of which this present application is a division. Hence the filamentsneed only be briefly described herein as consisting of a very finemetallic wire continuously solid throughout its length and whoseelectrical strain characteristics are predetermined. This wire may be ofsuitable and well-known material such as Constantan, Advance" andvarious other well-known materials having good resistance properties aswell as being capable of fabrication in small wire sizes. The filamentis preferably used in sizes of from approximately .001 to .003 of aninch in diameteri The filament is suitably bonded throughout itseffective length and insulated from the oppositely extending legs of theS-shaped strain responsive member "a by suitable bonding material suchas "Glyptal." The change in resistance of the filament in response tochanges in strain thereof may be measured by any usual Wheatstone bridgeemploying an osciilograph if necessary, such as is more fully disclosedin my said copending application but which does not constitute a part ofmy present invention.

In operation, a rotary impact load is imparted to crosshead '30 whichwill twist specimen 83 in a clockwise direction when looking down onFig. 2 thereby to subject two legs of the S-shaped member 3a to atension stress for resisting rotation of the upper fixed end of thespecimen. The strain imposed by the foregoing tension load in the 8member will correspondingly strain the fiilaments 84 and ll. 01' courseif the torque is applied in an opposite direction then the dynamometerarms or legs will be subjected to compression strains and measured bythe filaments in the same manner as for tension.

From the disclosure herein, it is seen that I have provided an extremelysimple, positive and effective means for measuring the torsional impactstress applied to a specimen which is often applied within a smallfraction of a second and hence it has heretofore been diillcult if notimpossible to determine the actual torsional load transmitted to thespecimen to produce failure thereof. My improved dynamometer is adaptedto be a permanent part of the impact testing machine because thes imencan be ruptured without injuring. or impairing the operativeness of theS-shaped dynamometer. While I have specifically shown my torsionaldynamometer for use with a torsional impact machine, yet it will ofcourse be understood that the principles of my torsional dynamometer maybe employed under other circumstances and in other machines.

It will of course be understood that various changes in details ofconstruction and arrangement of parts may be made by those skilled inthe art without departing from the spirit of the invention as set forthin the appended claims.

Iclaim: v

1 1' A torsional dynamometer comprising, in combination, a memberadapted to hav torque transmitted thereto, a rigid arm of fixed lengthconnected to said member substantially tangentialiy thereof, an end ofsaid arm being anchored to resist torsional movement of said member, andan electrical strain sensitive filament bonded throughout its efiectivelength to said arm so as to be responsive to the strain induced thereinby the torsional force.

2. A torsional dynamometer comprising, in combination, a member adaptedto have torque transmitted thereto, an arm connected substantiallytangentially to said member, an end of said arm being anchored forresisting torsional movement thereof whereby said arm is subjected to astraight line stress, and an electrical strain sensitive filament bondedthroughout its effective length to said arm and extending in a directionlengthwise thereof so as to be subject to strains in the arm induced bythe straight line stress thereof. 7

3. A torsional dynamometer comprising, in combination, an S-shapedmember having a central specimen engaging body portion, the oppositelyextending legs of said member being anchored to resist torsionalmovement or said body portion when torque is applied to the specimen,and a strain sensitive filament bonded throughout its eiifective lengthto a leg of said 8 member in a direction lengthwise or the leg so as tobe responsive to the lengthwise stress induced therein by said torque.

4. A torsional dynamometer comprising. in

combination, a member adapted to have torque transmitted thereto, arigid arm 0! fixed length connected to said member substantiallytangentially thereof. an end of said arm being anchored to resisttorsional movement of said member, and strain responsive means securedto said arm so as to be responsive to the strain induced therein by thetorsional force.

5. A torsional dynamometer comprising, in combination, an S-shapedmember having a central specimen engaging body portion, the oppositelyextending legs of said member being anchored to resist torsionalmovement of said body portion when torque is applied to the specimen,and strain responsive means secured to a leg of said 8 member so as tobe responsive to the lengthwise stress induced in such leg by saidtorque.

' EDWARD E. SIMMONS, Jr.

